This invention relates to a process for producing L-lysine, which comprises introducing a recombinant DNA of a DNA fragment containing a gene involved in the synthesis of dihydrodipicolinic acid synthase (hereinafter referred to as DDPS) or tetrahydropicolinic acid succinylase (hereinafter referred to as THPS), and a vector DNA into a microorganism belonging to the genus Corynebacterium or Brevibacterium, culturing the microorganism in a medium and recovering L-lysine accumulated in the cultured broth. Thus, the present invention relates to the field of bioindustry, and particularly to the field of producing L-lysine which is useful as a feed additive in the livestock industry.
Improvement of the so-called glutamic acid-producing microorganisms such as microorganisms of the genera Corynebacterium and Brevibacterium by recombinant DNA technology to increase L-lysine productivity is disclosed in Japanese Published Unexamined Patent Application Nos. 160997/81, 126789/83, etc.
Improving the process for producing a large amount of L-lysine using microorganisms is a continual problem. The present invention provides a solution to the problem by more effectively utilizing recombinant DNA technology.
The present inventors have found that a productivity of L-lysine can be improved by the use of a strain harboring a recombinant plasmid vector containing a gene involved in the synthesis of DDPS or THPS responsible for the biosynthesis of L-lysine.